1. Field of the Invention
This application relates to blow-molded containers, and more particularly to hot-fillable containers that are constructed to flexibly accommodate volumetric contraction that will occur in response to cooling of product within the container.
2. Description of the Related Technology
Perishable food and beverage products such as fruit juices are typically filled at elevated temperatures, such as 180 to 190 degrees Fahrenheit, under variable pressure conditions into specially designed plastic containers in what is conventionally referred to as the hot-fill process. Container designs that are intended for use with this process are referred to as hot fill type containers. After filling, the containers are sealed, preventing mass transfer into and out of the container. As the product within the containers cools, the volume that is occupied by the product decreases, thereby inducing a partial vacuum within the container that exerts an inward force upon the sidewall of the container. The design of hot fill type containers is heavily influenced by the necessity of managing this shrinkage during cooling. In the past, the shrinkage has most commonly been accommodated by molding one or more concave vacuum panel areas into the sidewall of the container that are designed to deflect inwardly as the product cools. By substantially limiting the deformation to the vacuum panel areas, unwanted distortion of other portions of the container is prevented. Such vacuum panel areas may serve the dual purpose helping consumers gain a better grip on the container during use after the container has been filled and distributed to the consumer.
While container designs relying upon vacuum panels have been effective in many ways, certain limitations and disadvantages are associated with their use, including limitations as to the possible variations in the exterior styling of the container, the need to provide enough plastic material to form the vacuum panels with the requisite thickness, and incompatibility with certain types of package labeling processes. For example, certain types of adhesive labels, especially clear labels, have a tendency to crimp in unsightly fashion due to flexure of the container during use with conventional hot fill container designs. Accordingly, a number of manufacturers find the presence of ribs and vacuum panels undesirable in their containers.
A need exists for an improved hot fillable container design without vacuum panels or ribs that obviates the various limitations and disadvantages of conventional hot fill container designs, such as the problem of label crimping.